Smart women know they need some fat in their diet. "But moderation is key — all oils have about 120 calories and 14 grams of fat per tablespoon," says nutritionist Ellie Krieger, R.D., host of Healthy Appetite on the Food Network. She suggests sticking to about two teaspoons of added fat per meal — and cooking with a variety of oils, since they all offer different body benefits. Here are some of the best kinds, plus delicious ways to get them in your diet.

Olive OilWhy it's healthy: Of all the oils, olive has the highest amount of heart-protective monounsaturated fats and polyphenols — antioxidants that have anti-inflammatory and anticlotting properties. It's also a staple of the Mediterranean diet, which has been shown to lower your risk of heart disease, lengthen your life, reduce your odds of cancer and diabetes, and help you lose weight. Newly pressed extra-virgin olive oil contains oleocanthal, a compound that acts similar to ibuprofen, according to a recent University of Pennsylvania study. Researchers say that a diet rich in olive oil may have pain-relieving and heart-health benefits similar to those of taking a low-dose baby aspirin every day.

What it's best for: Let extra-virgin olive oil's strong flavor shine though in salad dressings, on bread, or atop grilled meats, fish, and veggies. And (surprise!) you can fry or sauté with olive oil too! Frying isn't as unhealthy as you may think: "When you fry a food in olive oil that's heated to about 350 degrees F, a crust will form and your food will absorb less oil," says Nicki Heverling, R.D., program manager for the Mediterranean Foods Alliance. Just know that extra-virgin olive oil has a smoke point of about 385 degrees F to 420 degrees F — so keep an eye on the heat or else the oil will burn and splatter.

The skinny on olive oil: Choosing an olive oil can be confusing. Here, Heverling explains how to pick the best bottle.

Always choose extra-virgin. It's made from the first pressing of olives, so it has the most antioxidants and flavor. Look for an oil that's cold-pressed, meaning no heat was used during the processing. Think that's too pricey? Opt for an inexpensive extra-virgin olive oil for cooking, then splurge on a high-quality, unfiltered one for drizzling and dipping. "This adds amazing flavor and health to your food — it's worth every penny," says Heverling.

Go imported. Spain, Italy, and Greece are the biggest olive oil producers, and their strict quality standards mean you'll get a better product. Look for the words product of (as in "product of Italy") to guarantee that the oil comes from that country.

Buy dark-colored bottles. And keep them in a dark, cool place, since light and heat can turn oil rancid. Olive oil is best used within six months but can last for two years if stored properly.

Canola OilWhy it's healthy: Canola oil contains the lowest levels of unhealthful saturated fats of any oil, and it's also a good source of alpha-linolenic acid, a heart-healthy omega-3 fatty acid. The FDA recently approved canola oil products to carry the health claim that it may reduce the risk of coronary heart disease. Substituting it for other vegetable oils, and canola oil — based spreads for margarine, can significantly reduce the amount of saturated fats in your diet, according to a recent study.

What it's best for: Mild-flavored canola oil is the cheapest option for sautéing and frying, and it also works well as a shortening or butter substitute in baked goods.

Peanut and Sesame OilsWhy they're healthy: Consuming a diet rich in peanuts, peanut butter, and peanut oil may be as effective in protecting against heart disease as an olive oil-rich diet, according to a Penn State study. Peanuts contain resveratrol, an antioxidant also found in wine that has been associated with a reduced risk of cancer and heart disease. Sesame oil is a good source of vitamin E, magnesium, copper, calcium, iron, and vitamin B. It also contains sesamin and sesamolin, substances that have been shown to lower cholesterol and protect the liver.

What they're best for: These oils have a high smoke point, so they work best for stir-fries. Peanut oil has a bland, nutty flavor, making it an ideal choice in dishes featuring nuts or when you want other flavors in a recipe to shine. Sesame oil has a strong, distinctive taste. "I finish Asian dishes with a splash of toasted sesame oil," says Krieger.

Walnut and Flaxseed OilsWhy they're healthy: Both oils are high in omega-3 fatty acids. In fact, flaxseed has the highest concentration of omega-3s of all non-fish foods, and it also contains lignans, chemicals that may play a role in preventing cancer.

What they're best for: Their delicate flavor makes them ideal for no-cook items such as salad dressings and fruit smoothies; walnut oil can also be used for baking. Both oils must be refrigerated and used within a few months.